Heavily soiled wares can require multiple cleaning steps to remove the soils from the surfaces of the wares. Pots and pans used for prepping, cooking, and baking ware in full service restaurants can be particularly difficult to clean in a dishmachine due to the caramelized soil baked on to the surface of the ware. Some full service restaurants have attempted to overcome this issue by using, as a pre-step to washing the pots and pans in the dishmachine, a 3-compartment sink for soaking the pots and pans. Exemplary soaking solutions include water, pot and pan detergent solutions, or silverware presoaks. Components of these compositions typically include metal protectors, surfactants, alkalinity sources and the like.
Surfactants are the single most important cleaning ingredient in cleaning products. They surfactants reduce the surface tension of water by adsorbing at the liquid-gas interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid-liquid interface. When dissolved in water, surfactants give a product the ability to remove soil from surfaces. Each surfactant molecule has a hydrophilic head that is attracted to water molecules and a hydrophobic tail that repels water and simultaneously attaches itself to oil and grease in soil. These opposing forces loosen the soil and suspend it in the water.
Surfactants do the basic work of detergents and cleaning compositions by breaking up stains and keeping the soil in the water solution to prevent re-deposition of the soil onto the surface from which it has just been removed. Surfactants disperse soil that normally does not dissolve in water. Environmental regulations, consumer habits, and consumer practices have forced new developments in the surfactant industry to produce lower-cost, higher-performing, and environmentally friendly products.
Nonylphenol ethoxylates (NPEs) are predominantly used as industrial and domestic detergents as a surfactant. However, while effective, NPEs are disfavored due to environmental concerns. For example, NPEs are formed through the combination of ethylene oxide with nonylphenol (NP). Both NP and NPEs exhibit estrogen-like properties and may contaminate water, vegetation and marine life. NPE is also not readily biodegradable and remains in the environment or food chain for indefinite time periods.
An alternative to NPEs are alcohol ethoxylates (AEs). These alternatives are less toxic and degrade more quickly in the environment. However, it has recently been found that textiles washed with NPE free and phosphorous free detergents containing AEs smoke when exposed to high heat, e.g., in a steam tunnel in industrial laundry processes, or when ironed.
Surfactant is often incorporated into an oil-in-water microemulsion to make the products appear more homogenous. These cleaning products contain a variety of different surfactant systems in 5-20% solubilized oil which are then diluted with water prior to use. The surfactant systems generally employed in these cleaning products include a mixture of anionic or non-ionic surfactants and a short chain alcohol to help solubilize the oil phase and prevent liquid crystal formation. While short chain alcohols are effective, they also contribute to the volatile organic solvent content (VOC) of the product and pose
As can be seen there is a continuing need to develop effective, environmentally friendly, and safe surfactants and surfactant systems that can be used in cleaners of all kinds, particularly soaking compositions.